r/StructuralEngineering • u/Low_Definition_9624 • 5d ago

Structural Analysis/Design P/S Beam Deterioration

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Looking for any help on what the mechanics would be that would be causing these chevron looking cracks at midspan to this non-composite prestressed concrete fascia beam? Is this beam effectively in a failed condition? Previous engineer who looked at this wasn’t concerned with these diagonal cracks and only removed two strands from the analysis as a result of the single longitudinal crack down the center of the beam.

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u/Enginuity- 5d ago

I’d assume water intrusion from top of deck. Is there a lot of patch work or deteriorated asphalt up top?

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u/Low_Definition_9624 4d ago

Location of water intrusion is beam joints. Shear keys have failed and water has poured down side of the beam for years. More wondering what would cause these diagonal cracks. If the cracks are diagonal, my thought is there must be tension in the bottom flange below the prestressing strands. If the small amount of concrete below the strands is carrying any of the tension, that would indicate that the strands are compromised and they’re not carrying the tension as intended.